Abstract

ROSSI, Carlos A et al. Chemical composition, total polyphenols content and nutritional value of browsing species at the silvopastoral system in Argentinean arid Chaco. Zootecnia Trop. [online]. 2008, vol.26, n.2, pp.105-115. ISSN 0798-7269.

The objective of this study was to determine the chemical composition, total polyphenols content (TPC), and nutritional value of the main browsing species of the Argentinean arid Chaco. The results showed that crude protein (CP) registered a range between 19.4% for Mimozyganthus carinatu and 10.2% for Aspidosperma quebracho-blanco. For neutral detergent fiber, the values were high for Acacia aroma (46.7%), Prosopis flexuosa (44.3%), and A. quebracho-blanco (42.3%) and minimum for Bulnesia foliosa (17.9%). For acid detergent fiber, A. aroma had the maximum value with 41.2% and B. foliosa with the lowest, 13.8%. For TPC, the highest values were 24.3 and 14.4% for Larrea cuneifolia and Larrea divaricata, respectively, while the lowest values were 3.6, 3.4, and 1.2% for A. aroma, A. quebracho-blanco, and Celtis pallida, respectively. The in situ degradability analyses for dry matter (ISD DM) and CP (ISD CP) were carried out at 24 and 48 h. For ISD DM at 24 h, B. foliosa (86.7%), C. pallida (72.1%) and L. divaricata (67.9%) were the species with the highest values. The smallest values were for M. carinatus (44.5%), Prosopis torquata (44.2%), and A. aroma (27.1%). For ISD DM at 48 h, the species grouped in similar form. The ISD CP analyses showed values greater than 70% in most of the species (B. foliosa, C. pallida, L. divaricata, A. quebracho-blanco, L. cuneifolia and P. flexuosa). For both lapses, B. foliosa showed the higest values (91.7 and 91.3% for 24 and 48 h, respectively) and A. aroma with the lowest (18.4 and 16.8% for 24 and 48 h, respectively). Positive correlations were not detected among TPC and ISD DM and ISD CP. probably due to the TPC method used is not specific for tannins.

Keywords : crude protein; fiber; in situ degradability; xerophytic forest; goats; cattle.